The Wayne Madison Road at Hamilton Trenton Road intersection is part of a critical Butler County, Ohio corridor and serves as one of the only direct north-south routes from the nearby City of Trenton over the Great Miami River. The skewed intersection caused significant traffic congestion and safety concerns because of the poor geometry, lack of turn lanes and a railroad crossing just south of the intersection. With ten reported crashes per year and major traffic delays, the Butler County Engineer’s Office (BCEO) sought a solution that would improve traffic flow and safety for the area. A traffic study was conducted to determine if a signalized intersection or a roundabout would be the most beneficial and a roundabout was determined to be the optimal solution.
BCEO selected Burgess & Niple (B&N) to design improvements to the highly skewed intersection with four legs, two lanes and no turn lanes. B&N prepared the preliminary horizontal layout of three roundabout configurations at the intersection which included a circle, an oval, and a peanut shape for review by the County. B&N proposed the oval-shaped roundabout that BCEO selected as the preferred alternative. The final design of the county’s first multi-lane modern roundabout includes curb and gutter, safer road geometrics and improved storm drainage.
The intersection consisted of four skewed two-lane legs with no turn lanes, increased peak hour traffic, heavy truck traffic, poor geometry, no turn lanes, and traffic delays due to a railroad crossing 950 feet south of the intersection were all contributing factors to the major congestion and safety issue. The design had to accommodate stopped traffic that would back up into the intersection when the train tracks are in use. The additional lanes in the multi-lane allowed for east-west traffic flow and provided additional room for vehicles during a train event. In addition, actuated warning signs were designed to stop north-south traffic from entering the roundabout when a train was crossing, keeping the east-west legs open and operational during this event, improving capacity and safety for the roundabout.
In addition to traffic volume and safety concerns, the area is too flat to drain water. The new design incorporated a closed drainage system to remove stormwater runoff from the paved area, increasing the requirements for both quantity and quality of the drainage system design. The solution was a combination of small drywells collecting ditch drainage, a stormwater BMP structure to remove pollutants, and a combination detention/infiltration basin that prevents ponding in the roadway and provides the time to infiltrate the stormwater into the aquifer.
The solution designed by B&N for the BCEO addressed the traffic congestion and safety concerns at this skewed intersection. The unique and innovative oval roundabout shape addressed the geometric challenges while minimizing right-of-way impacts, avoiding roadway realignment and pulling away from the nearby church. The improved safety of this intersection is a contributing factor in the 100% reduction of serious and fatal crashes in Butler County roundabouts, outperforming the national average of 90%.
The Wayne Madison Road at Hamilton Trenton Road Roundabout received the 2022 Project of the Year Award from the American Society of Highway Engineers Triko Valley Section and Great Lakes Region.